Field of the Invention
The present invention relates to a reading apparatus and a recording apparatus.
Description of the Related Art
Japanese Patent Application Laid-Open No. 2005-8283 discusses an apparatus including an elevating unit that raises and lowers a sheet feeding tray, including a gear, a rack, and a motor, and an elevation control unit that controls the rise and fall of the sheet feeding tray using an optical sensor. According to the apparatus discussed in Japanese Patent Application Laid-Open No. 2005-8283, a stacking capacity on a sheet discharge tray can be increased as the number of documents on the sheet feeding tray decreases. Therefore, the apparatus can feed a large amount of documents while the apparatus is reduced in space.
However, in the apparatus discussed in Japanese Patent Application Laid-Open No. 2005-8283, the height of the stacked documents is detected using the optical sensor, and the rise and fall of the sheet feeding tray is controlled based on a detection result. Therefore, the optical sensor may react only if the thickness of the stacked documents is changed to some extent, so that the decrease in the number of the documents on the sheet feeding tray and the rise of the sheet feeding tray and a sheet discharge unit (sheet discharge roller) are not interlocked with each other. Accordingly, the height of the sheet discharge unit needs to be determined while allowing for a period elapsed until the optical sensor detects the change in the thickness of the stacked documents, which has been disadvantageous to reduce the height of the apparatus.
Further, even if a sheet feeding and discharge unit is reduced in space, use of mechanism components such as a gear and a rack for an elevating device results in a complicated structure. Therefore, it may be difficult to reduce the size of the apparatus. To provide the elevating device, a control error of the elevating device and a clearance of an operation unit need to be considered, which has been disadvantageous to reduce the height of the apparatus.